This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.
In conventional power transmission belts, the belt has an inner compression section, an outer tension section, and an intermediate neutral plane. Typically, helically wound reinforcing cords are located within the neutral plane and so the neutral plane is also referred to as the load carrying zone. Such belts also having a variety of groove and rib configurations, using longitudinal or transverse grooves or a combination of both. The grooves are located in the inner compression section of the belt. The grooves assist in engaging a pulley in the power transmission system. For some belts, grooves and rib configurations may also be provided in the outer tension section.
The reinforcing cords in the load carrying zone provide a majority of the tensile strength to the belt. Thus, the materials forming the belt are important. It is known to use high modulus material for the reinforcing cords, including the use of poly(p-phenylene-2,6-benzobisoxazole). However, due to the distinct physical properties of the PBO yarns, simple substitution of PBO yarns for known polyester or aramid cords in power transmission belts may not yield a belt having acceptable performance properties.
Typical low modulus belts utilize a low modulus tensile member to provide the elongation necessary to provide installation and maintain tension during the functional life of the belt. There are severe limitations placed on the selection of the proper tensile member component because it must stretch to maintain tension and installation and this stretch or low modulus also limits the operating belt tension and power transmission due to this low modulus.